Getting Started with Totient

Totient is a calculator that speaks tape measure. Instead of forcing you into decimals, it takes feet, inches and fractions exactly as you'd read them off the blade — and hands the answer back the same way. Here's how to get going in about five minutes.

The ft / in button

Almost everything in Totient runs through one clever key: the ft / in button. It lets you build a measurement in parts — type a number, tap the button to lock it in, type the next part, tap again. The button even tells you what's next: before you've set the feet it reads ft ', and the moment feet are locked it flips to in ". The label is always a hint for your next tap.

So to enter 12' 6":

1. Type 12, then tap ft ' — the 12 locks in as feet, and the running display shows 12'.
2. Type 6, then tap in " — the 6 locks in as inches, and the display reads 12' 6".

Because each part is committed on its own, there's no decimal point to fumble and nothing to convert in your head — what you tap is exactly what you read off the tape.

Just inches? Type the number and tap the button twice. The first tap sets it as feet; the second moves it over to inches — so 6 · ft' · in" gives you 6".

Adding the fraction

Fractions go through the / key. Type the top number, tap /, type the bottom number, then tap ft / in once more to attach the fraction to the inches you just entered. Finishing 12' 6-1/2" from above is just 1 · / · 2 · in ".

End to end, the whole measurement is a steady left-to-right rhythm — 12 · ft · 6 · in · 1 · / · 2 · in → 12' 6-1/2" — entered the same order you'd say it out loud.

Adding, subtracting and scaling

The operations work like any calculator, but on real measurements:

• Add and subtract two lengths — 12' 6" + 3' 9-1/2" = 16' 3-1/2" — with the carrying and borrowing handled for you.
• Multiply and divide to scale: double a part, or split a 97-3/8" span into 5 equal gaps without the long division.

If you've ever done this by hand, you'll appreciate not having to find a common denominator ever again.

Converting units

Open the conversions sheet to move a result between inches, feet, yards and more. Because Totient keeps measurements as exact fractions internally, switching units never introduces the rounding error you'd get converting by decimal.

Area and Volume modes

The three tabs across the top — Length, Area and Volume — change what the keypad solves for. Length is the everyday add, subtract and scale calculator above. The other two multiply dimensions together:

• Area multiplies two dimensions — length × width — into square feet. Enter 12' 6" × 10' 3" and read the answer in ft² (with in², yd² and m² a tap away). It's the fastest path through the square-footage math for flooring, paint and tile.
• Volume adds a third dimension — length × width × height — into cubic feet. Enter 8' × 4' × 6" for a slab, or any three measurements, and read the answer in ft³ (with in³, yd³ and m³ alongside). Handy for concrete, gravel, soil and mulch.

In both modes you separate the dimensions with the × key and finish with = — entering each dimension with the same ft / in and / keys you already know.

Carrying a result into the next mode

This is the part that saves real time: Totient can hand the answer from one mode straight to the next. Work out a Length, press =, then tap the Area tab — your length is carried in as the first dimension with a × already waiting, and a hint reads "Carrying 5' 3" — enter width, then =". Type the width, press =, and you have the area without re-entering a thing.

The same hand-off runs from Area to Volume: your square footage carries over as the base and you just add the height. The carry only happens when it makes dimensional sense — length into area, area into volume — so you can never accidentally multiply by the wrong kind of value. Switch the other direction, or jump straight from Length to Volume, and Totient simply starts you fresh.

History and working offline

Every result is saved to a running history, so you can scroll back to that wall measurement from twenty minutes ago instead of re-measuring. And the whole app runs fully offline — no signal needed in the garage, the basement or the middle of a job site. There's no account, no sign-up, and your measurements never leave your phone.

That's the whole app. The best way to learn it is to keep it in your pocket on the next project — start with a sum you'd otherwise dread, like adding two odd lengths.